Compiani imp_ok 22/02/21 18:09 Pagina 51 R. Compiani et al. Large Animal Review 2021; 27: 51-56 51 Prevention of the main Clostridial diseases in cattle N R. COMPIANI1, S. GROSSI1, L. LUCINI2, C.A. SGOIFO ROSSI1* 1 Dipartimento di Scienze Veterinarie per la Salute, la Produzione Animale e la Sicurezza Alimentare (VESPA) - Università degli Studi di Milano 2 Dipartimento di Scienze e Tecnologie Alimentari per una filiera agro-alimentare sostenibile (DiSTAS) - Università Cattolica del Sacro Cuore SUMMARY Clostridial diseases of cattle are an economic and welfare issue worldwide. Clostridia are obligate anaerobic spore-forming gram- positive bacteria able to cause a wide range of pathologies in humans and animals. Pathogenicity is expressed by sporulation in favourable environmental condition with release of toxins. Toxins produced and tissues damaged are generally characteristic for each clostridial. The incidence of clostridiosis is relatively low however the outcome is generally very poor despite the bacteria being sensitive to the most common antibiotic therapies. The generally rapid course of the disease prevents any intervention. Despite a continually developing classification, clostridium that affect cattle can be classified based on their target tissue and path- ogenic expression, as neurotoxic, histotoxic and enterotoxic. Scientific knowledge about different clostridial toxins, their ae- tiopathological mechanisms, risk factors and pathologies involved are generally limited due to the large number of bacteria strains and types involved. Alongside the more studied neurotoxic C. tetani and C. botulinum for their implications in human medi- cine, there are lots less known pathogenic strains capable of causing extremely severe clinical patterns in veterinary medicine. In particular regarding enterotoxic clostridia, the incidence of necro-haemorrhagic enteritis and enterotoxaemia is probably wrong- ly estimated because complete post-mortem investigation is rarely performed and several other reasons can lead to sudden death. The aim of this review is to describe the main clostridial diseases that can affect cattle and some of the possible prevention strate- gies as controlling major known risk factors and the use of vaccination. KEY WORDS Clostridia, clostridiosis, cattle. INTRODUCTION Bovine clostridiosis The classification of clostridia is a continually developing top- Clostridia are obligate anaerobic spore-forming gram-positive ic for researchers and is mainly based on the types of toxins bacteria. The genus Clostridium consists of dozens of strains produced. From a practical point of view, clostridium that af- characterized by different pathogenicity, many of which are able fect cattle can be classified based on their target tissue and to cause illness in humans and other animals. Pathogenicity is pathogenic expression, as neurotoxic, histotoxic and entero- expressed not by the presence of clostridial bacteria but by repli- toxic (Table 1). cation; in favourable environmental conditions, sporulation with release of toxins takes place. Clostridial toxins are biological- Neurotoxic clostridia ly active proteins that are antigenic in nature. Toxins produced The main neurotoxic clostridia which affect cattle are C. tetani and tissues damaged are generally characteristic for each and C. botulinum. Tetanus is an acute, often fatal disease of al- clostridial1. In beef and dairy rearing systems, clostridium-as- most all domestic animal species caused by the neurotoxins pro- sociated diseases are both a welfare and an economic issue. duced by Clostridium tetani in anaerobic conditions. This usu- The incidence of clostridiosis is relatively low however the out- ally develops after contamination of deep and penetrating come is generally very poor despite the bacteria being sensi- wounds. The neurotoxin produced causes the characteristic tive to the most common antibiotic therapies. The rapid course rigidity and muscle spasms2-4. C. tetani is present in soil and of the disease, in most cases, prevents any intervention. The aim faeces and there can be several means of entry into the animal. of this review is to describe the main clostridial diseases that Published literature reports infections of the umbilical cord, can affect cattle and the prevention strategies that field vet- infection of wounds caused by barbed wire or pitchfork injuries, erinarians can implement to support the farming system. injection sites, hoof and interdigital space lesions, oral mucosal wounds caused by coarse forages, vaginal laceration incurred during dystocic calving, uterine prolapse or placental extrac- tion, bedsores or surgical site lesions, dehorning and castration Corresponding Author: activities. Penicillin or tetracycline treatment to reduce bacte- Carlo Angelo Sgoifo Rossi ([email protected]). ria proliferation in addition to anti-tetanus homologous Compiani imp_ok 22/02/21 18:09 Pagina 52 52 Prevention of the main Clostridial diseases in cattle Table 1 - Bovine clostridiosis classification. Type Strain Pathology Neurotoxic clostridia C. tetani Tetanus C. botulinum Botulism Histotoxic clostridia C. septicum C. chauvoei C. novy Gangrene or tissue infections (muscles or muscles fascia, subcutaneous tissue, liver, abomasum, kidney, etc.) C. sordellii C. perfringens C. haemolyticum Enterotoxic clostridia C. sordellii Enteritis and Enterotoxaemia C. perfringens C. septicum C. difficile serum and careful wound/entry site disinfection can improve sidered to be an ‘‘endogenous’’ disease1,12-14. Even without a con- prognosis. Considering the aetiology, prevention should be sensus from the scientific world about blackleg pathogenesis, based on improving the hygiene of the housing environment the infection is acquired by the ingestion of C. chauvoei and farming/vet tools5. spores that are transported from the intestine to the muscles Botulism is a neuro-paralytic disease of humans and animals, and tissues by macrophages across Peyer’s patches. Other hy- caused by the neurotoxins produced by Clostridium botulinum. potheses include entry by oral mucosal wounds due to C. botulinum is a ubiquitous soil-borne pathogen that finds an teething, forestomach traumatic injures by foreign bodies and excellent growing environment in decaying organic matter6. In lesions of the enteric mucosa15-17. The spores remain dormant cattle, the signs are generally associated with the ingestion of in the target tissues until a traumatic injury induces the anaer- feed or water contaminated with the remains of carcasses. There obic conditions ideal for their germination, multiplication and are even reported outbreaks linked to contact with poultry lit- toxin production17-18. The predisposing traumatic events re- ter. Furthermore, C. botulinum can directly proliferate in for- ported include bumps, blows, mounting behaviour, competi- ages without carcasses, in cases of inaccurate collecting and stor- tion at the feed bunk or at water points, constricted passing in age procedures (presence of organic refuse, excess soil con- narrow places, goading and transport in general5. This infec- tamination, high humidity and temperature)5,7-8. Botulism usu- tious disease is acute and globally spread among ruminants, ally results in fatality since the neuronal flaccid paralysis can- causing significant loss in livestock production19 as it is gen- not be reversed by available therapeutic options except for ad- erally fatal, being included among the causative agents of sud- ministration of antitoxin9. Its prevention is simply based on den death. The disease is typically observed during the warm good management practice during harvesting and storing feed. season, and young cattle aged between 6 to 24 months are most- ly affected18. C. chauvoei is one of the clostridia supporting a Histotoxic clostridia fatal hyperacute form counted among the causative agents of Among the different pathologies caused by histotoxic clostridi- sudden death. Moreover, the classical forms are reported al strains, the two main diseases affecting cattle are ‘Blackleg’ with swelling and crepitus of affected skeletal muscles due to and ‘Malignant oedema’. The differences between these two dis- a neutrophilic necrotizing myositis20. Rarely diagnosed forms eases include the clostridial strains implicated and the entry include fibrinous pleuritis, pericarditis, epicarditis, menin- point into the animal. goencephalitis, severe acute necrotizing enteritis or myositis of Malignant oedema is considered to be an ‘‘exogenous’’ disease sublingual muscles and diaphragm21-25. Avoiding soil-con- because different clostridia, such as C. septicum, C. chauvoei, taminated pasture, forages and litter is the most effective pre- C. novyi, C. sordellii, and C. perfringens, from the environment ventive strategy especially in those regions characterized by very gain access into the tissues after skin or mucosal wounds and high annual rainfall that can expose and activate latent spores, development of an anaerobic environment. Main types of trau- after soil excavation or areas with a history of flooding25-26. ma that may lead to malignant oedema include, but are not re- stricted to, intramuscular injections, parturition, shearing, cas- Enterotoxic clostridia tration, surgery and tail docking10-11. Clinically, the involved tis- Among enterotoxic clostridia, Clostridium perfringens is the ma- sues rapidly develop oedema, characterised by a variable jor cause of necrotic and haemorrhagic enteritis and entero- presence of gas, high fever and